Novel photoactive polymer composites for use in the degradation of organic wastes

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Abstract

The objective of this work was to test the feasibility of combining photoactive dyes, titania, and polymers to create various novel polymer composites. The composite materials were synthesized by functionalizing TiO 2 -based materials with visible-active dyes, followed by integrating the functionalized TiO 2 into traditional polymeric materials. It was hypothesized that there would be a substantial increase in the antifouling activity of the material when combining all three components (visible-active dye, titania, and polymer hydrogel) into one composite. The materials were characterized by a variety of traditional techniques, including thermogravimetric analysis (TGA), Fourier-transform infrared spectroscopy (FT-IR), and ultraviolet-visible spectroscopy (UV-Vis). In addition, the polymer composites were tested in a photoreactor under UV light to qualitatively measure how well they degrade model organic wastes. All of the different polymer composites tested in the reactor reduced the concentration of 4-nitrophenol (4-NP) by at least 50% in 5 hours. The best performing composite was the combination of P25 and rhodamine B, which reduced the concentration of 4-NP by 87.6% in 5 hours. As UV irradiation time was increased beyond 5 hours, the concentrations of 4-NP decreased even further. On more than one occasion, leaching of titania from the polymer compositess was observed. These observations suggest the next step toward making this experimental setup viable is to introduce covalent linker molecules between the dye molecules and the surface of the titania.